A process for texturizing polycrystalline silicon (hereinafter also "polysilicon" or "poly") is discussed in an article entitled "Rugged Surface Poly-Si Electrode and Low Temperature Deposited Si3N4 for 64 Mb and Beyond STC DRAM Cell" authored by M. Yoshimaru et al., Oki Electric Industry Co., Ltd., VLSI R&D Laboratory 550-1, Higashiasakawa, Hachioji, Tokyo 193, Japan. In this article, using a poly deposition temperature of 570 degrees Celsius causes the poly layer surface to become rugged (or textured). The article claims (in the third paragraph of the first page) that applying this technique to form a storage node cell plate of a dynamic random access memory's (DRAM) storage stacked capacitor, results in an increase of the cell plate's surface area of up to 2.5 times that of a standard stacked capacitor cell (STC).
Two main drawbacks with this method are the facts that, 1) the temperature must be precisely controlled (within +/-3 degrees C of 570C.) during deposition to form the rugged poly surface; and 2) subjecting the rugged poly to temperatures above 570 degrees C. in subsequent process steps will cause the rugged surface to flatten out.
In the present invention, a stable and uniform texturized poly surface is developed that will retain its textured surface throughout implementation of conventional DRAM fabrication processes.